 this.map.addSource('maine', {
                'type': 'geojson',
                'data': {
                    'type': 'Feature',
                    'geometry': {
                        'type': 'Polygon',
                        // These coordinates outline Maine.
                        'coordinates':[
    [
        103.31740025897386,
        23.56061508347915
    ],
    [
        103.3174129048389,
        23.56060758418701
    ],
    [
        103.31737193057565,
        23.560595113759746
    ],
    [
        103.31732229950185,
        23.560649969156433
    ],
    [
        103.31741829396674,
        23.560631477590647
    ],
    [
        103.31742432832786,
        23.56062359269247
    ],
    [
        103.31739941919736,
        23.560616011653167
    ],
    [
        103.31743128830988,
        23.56062571094775
    ],
    [
        103.31742310391621,
        23.560636405221658
    ],
    [
        103.31745024200018,
        23.560644664638065
    ],
    [
        103.31746987650956,
        23.560619008880295
    ],
    [
        103.317447366031,
        23.560587147898445
    ],
    [
        103.31740025897386,
        23.56061508347915
    ]
]
                    }
                }
            });
            // Add a new layer to visualize the polygon.
       map.addLayer({
                'id': 'ceshi',
                'type': 'fill',
                'source': 'maine', // reference the data source
                'layout': {},
                'paint': {
                    'fill-color': 'red', // blue color fill
                    'fill-opacity': 0.5
                }
            });